Refrigerating apparatus



Dec. 22, 1931. H. B. HULL 1,337,258

REFRIGERATING APPARATUS Filed July 30, 1927 2 Sheets-Sheet 2 5 r A" I glwwzntv 2 Sheets -Sheet Filed July so,

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5 BM 3 2 m QM v Q? M To v ll 4 Mfi m vu fine; w E 1 mm a v LUWKUEEOO A r Lu 8 L E3uw N- vwiv fiwv mm 4 Patented Dan. 22'. 1931 HARRY B. Hill I'LL, 0F DAYTON, OHIO, 'ASSIGNOR, BY MESNE ASSIGNMENTS, TO FRIGIIO- AIRE CORPORATION, A CORPORATION OF DELAWARE REFRIGERATING- APPARATUS Application filed July 30,

This invention relates to refrigerating apparatus of the absorption type, and particularly to arrangements for controlling the refrigerant in such systems.

It is among the objects of the invention to improve the efficiency of absorption systems, and to provide improved means for controlling the flow of refrigerant from one part of the system to another. It is particularly an object to provide improved means for preventing condensation of gaseous refrigerant in the refrigerating chamber or evaporator and to provide an improved arrangement. for withdrawing gaseous refrigerant from the evaporator.

Another object of the invention is to provide means for cooling the condensed refrigerant before permitting it to enter the evaporator or refrigerating chamber.

Still another object is to eliminate the necessity for brine tanks and similar holdover devices iisually associated with the evaporator.

Further objects and advantages of the present invention will be apparent'from thefollowing description, referen'ce being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown. v

In the drawings Fig. 1 is a diagrammatic .representation of the invention applied to ah absorption system;

Fig. 2 is a plan of a control valve, and

Figs. 3and 4 are vertical sections of the valve on the lines 3-3 and 4+4 respectively of Fig. 2. i F g In Fig. 1, l0 is a generator-absorber which may be intermittently heated bya gas burner 11 to supply gaseous refrigerant through a conduit 12 to a condenser 13, which in turn delivers the refrigerant to a receiver 14 and evaporator 15. The generator-absorber may be intermittently cooled, by water flowing through a jacket 16', to absorb the refriger ant evaporated in the evaporator15. The devices thus far mentioned are conventional and may be of any suitable form. The generator-absorber may be charged with solid absorbent, such as calcium chloride, the re- 1927. Serial No. 209,557.

frigerant in such case being ammonia. Refrigerant is both taken from the generatorabsorber during the generating phase, and returned to it during. the absorbing phase, through the pipe 12.

The following apparatus is used to control the generating and absorbing phases of the operating cycle. Water under pressure flows constantly from any suitable source 20 to a water switching device .21, having a valve 22,.which in its lower position directs the flow through pipe 23 to the cooling jacket 16, and in its upper position directs the flow through the pressure operated gas valve 24 and pipe 25 to the jacket 26 of the condenser 13. The water switch valve ,is normally held in its lower position by a spring 27 and may be held in its upperposition against the force of the spring by a solenoid 28, energized by current from a source 29,-under the control of a switch 30 which is operated by a thermostat 31 placed in the generator-absorber. v

Gas is supplied from the main 32 to a constantly burning pilot 34 and tothe gas valve 24.

When the generator-absorber is cold, the switch 30 closes the circuit to the solenoid 28. Current being supplied at, 29, the solenoid switches the water to the gas valve and condenser. The gas'valve is opened by the pressure of the water, and the burner is lighted by the pilot. The generator is heated, g ving ofi' gaseous refrigerant, which is condensed in the condenser 13.- The condensed refrigerant is supplied to the evaporator, in a manner to be described. When the generator reaches a predetermined temperature, the thermostat 31 opens the switch 30, de-energizing the solenoid and permitting the valve 22 to move downward under the force of the spring 28. This switches the water from the gas valve'24 and thecondenser to the absorber cooling jacket 16. Failure of water pressure closes the gas valve, extinguishing the burner, and water flowing through the jacket cools the absorbent and initiates the absorbing phase. This continues until the generator has cooled to a predetermined temthe switch to repeat the cycle.

Suitable safety controls may be provided such as a fusible link 40 in. the generator-absorber which breaks the solenoid circuit when an excessive temperature is.reached, and a Bourdon tube 42 which closes a switch 43, short circuiting the line to blow fuses 44, thus opening the circuit whenever an excessive pressure is developed.

In previous systems of the type described, much difficulty has been encountered in controlling the passage of refrigerant between the condenser and evaporator. When the generating phase begins, the evaporator is much colder than the condenser. Consequently, if the conduit between the condenser and evaporator is open, some refrigerant vapor will pass through the condenser-and liquefy in the evaporator, liberating heat, which is objectionable. Float valves have been proposed to insure that only liquid refrigerant will How to the condenser, but these are objectionable for many reasons. Primarily the systems having float valves do not cool the liquefied refrigerant before it flows into the evaporator. Consequently the refrigerant must be cooled in the evaporator before e'lfective refrigeration is produced. This results in a loss of efficiency by heating the space to be refrigerated. Ordinarily the evaporators are equipped with 'holdover devices such as brine tanks, which being very cold, absorb heat from the refrigerant entering the evaporator. Moreover float valves as heretofore constructed are delicate and apt to get out of order, and they do notentirely solve the problem of controlling the refrigerant. My invention contemplates means forcondensing, collecting and cooling all the refrigerant outside the evaporator during the generating phase, and dumping the cooled refrigerant into the evaporator when the absorbing phase begins. By dumping I mean causing the liquid refrigerant to flow rapidly into the evaporator from the receiver, regardless of how such flow may be produced I also arrange the circuit so that the refrigerant will be drawn positively into the evaporator by the suction produced in the absorber. v

In'accordance'with my invention, the re- C(BIVBI', condenser and evaporator are connected to each other through the device shown in Figs. 2-4, which I term a pressure-responsive dump valve. This includes a casing 50 having a chamber 51 which receives liquid and whatever gaseous refrigerant comes from the condenser through the passage 52. 'A. second chamber 53 communicates with chamber 51 through a passage 54 under the control of a valve 55. The second chamber may be given any desired capacity by having the receiver 14 connected thereto through passages 56 and 57. The receiver is suitably insulated to prevent the transmission of heat from the atmosphere to the refrigerant within it. The chamber 53 discharges liquid refrigerant only, to the evaporator through the passage 60 under control of the valve 61. The

evaporator is also connected directly to the condenser through a connection 62 (Fig. 1) which by-passes the receiver and chamber 53. This connection discharges into the chamber 51 through a passage 63 in a boss 64 forming part of the casing 50. This passage is controlled by a valve 65.

It will be noticed that the three valves are in alignment and all are mounted on a valve stem 66 which is slidable in guides 67 in chamber 53. The valve stem is attached to a yoke 68, which passes around the boss 64 as shown in Fig. 4 and is secured to a spring cup 70 hermetically sealed to one end of a metal bellows 71, the other end of which is sealed to and closes the top'of the chamber 51. A spring 73 in the cup bears against an adj ustable stop 74 on a yoke 75 attached to the easing. The spring urges the valve stem downward while pressure of fluid in the chamber 51 urgesthe stem upward.

' Each valve is adjustable on the stem 66, and all are so adjusted that when the stem is in its uppermostposition, valves 61 and 65 are closed while valve 55 is open. In the lowermost position of the stem the valve 55 is closed and both other valves are opened.

The device operates as follows. When the generating phase of the cycle of operationbegins, refrigerant vapor is driven off from the generator-absorber and enters the condenser and chamber 51, and the pressure within the condenser and chamber 51 rises very rapidly.

By the end of the generating phase, the pressure within the system has increased vto a value greatly above that necessary to close the valves, for example, to 250 pounds per square inch. At the end of the generating phase the automatic control devices previously described stop the heating and initiate the cooling or absorbing phase. WVhen thisoccurs, the pressure within the generator, and consequently in the condenser, is reduced. During the reduction of pressure from this. value to the value at which the valves 61 and 65 were closed, some of the refrigerant in the receiver will evaporate, and due to the insulation of the receiver from the atmosphere, the latent heat necessary for this evaporation will be supplied by the liquid refrigerant itself. Consequently the remaining liquid will be rapidly cooled. When the pressure has been reduced below 70 pounds, the bellows will collapse under the action of the spring, which unseats valves 61 and 65 and seats valve 55. This establishes communication between the receiver and the evaporator and from the evaporator through the condenser, to the generator-absorber. The liquid refrigerant in the receiver then flows into the evaporator.

Reduction of pressure in the evaporator through the line 62 causes an immediate and rapid discharge of the refrigerant in the receiver through the passage into the evaporator under all conditions. If the evaporator is colder than the receiver and is placed below it, the refrigerant will flow naturally into the evaporator. If the evaporator is warm, as when the apparatus is first operated, the refrigerant vwould start to flow into the evaporator. Here it would vaporize, and the vapor, if it were not removed from the evaporator, would cause enough pressure to prevent further flow. Under these conditions the vapor is withdrawn by the connection 62 as fast as it forms, and the refrigerant can flow rapidly even into a warm evaporator. The connection 62 also furnishes means for positively drawing the liquid refrigerant into the evaporator, for example where the evaporator is not below the level of the receiver. When the valve 55 closes, there will be a pressure in the receiver corresponding to the vapor pressure of the refrigerant at the receiver temperature. The absorber, through the connection 62 will produce a low pressure in the evaporator, a lower pressure than that existing in the receiver. Consequently the liquid will be forced or drawninto the receiver by this difference in pressure. The refrigerant entering the evaporator has. been cooled in the receiver toa temperature somewhere near that to be maintained in the evaporator. Consequently substantially all of the heat absorbed by the refrig erant in evaporating is taken from the space to be refrigerated, there being little .loss caused by cooling the refrigerant after it enters the evaporator. The-refrigerant gradually returns the refrigerant to the gen-. erator-absorber through line 62, chamber 51 and the condenser. When all the refrigerant has been absorbed, the thermostat closes th switch to repeat the cycle.

While the form of embodiment of the invention as herein disclosed, constitutes a prevoir for liquid refrigerant, and an evaporator connected in an operative circuit, said circuit including a connection between the reservoir and evaporator'and a connection between the evaporator and generator-absorber; a device responsive to the pressure in the system for opening and closing the connection between the reservoir and the evaporator and for opening and closing the connection between the evaporator and the generator-absorber.

2. Absorption refrigerating apparatus including in combination, a generator-absorber, condensing means including a reservoir for liquid refrigerant connected to the generatorabsorber, an evaporator connected to the reservoir, a connection between the evaporator and generator-absorber by-passing the reservoir, and a device responsive to the pressure of the system for closing and opening the connection between the reservoir and the generator absorber, for opening and closing the connection between the reservoir and the evaporator, .and for opening and closing the by-pass connection between the evaporator and generator-absorber.

3. Refrigerating apparatus including in combination an insulated receiver, means for supplying liquid refrigerant thereto and withdrawing gaseous refrigerant therefrom, a refrigerating chamber connected to the receiver and means for closing the connection between the receiver-and refrigerating chamber, when refrigerant is supplied to the receiver and for opening the connection after the first-mentioned means has withdrawn a portion of the refrigerant therefrom.

' 4. Absorption refrigerating apparatus including in combination a generator-absorber, condensing means including a reservoirfor liquid refrigerant connected to the generatorabsorber, an evaporator connected to the reservoir, a connection between the evapora tor and generator-absorber by-passing the reservoir, and a device responsive to a predetermined high pressure in the system for closing communication between theevaporator and the rest ofthe system and for opening the connection between the reservoir and the generator-absorber, said device being responsive to apredetermined low pressure for closing the connection between the generatorabsorber and reservoir and opening the connection between the reservoir and the evaporator and the by-pass between the evaporator and the enerator-absorber.

' 5. Re rigerating apparatus comprising in combination means for alternately generating and absorbing gaseous refrigerant, a condenser, a receiver connected to the condenser, an evaporator connected to the receiver and having a by-pass connection to the condenser, and a device responsive to the pressure of the condenser for closing communication between the evaporator and the rest of the system, and opening communication between the condenser and reservoir, said device being 'adapted to close communication between the condenser and receiver, and open both evaporator connections.

6. Refrigerating apparatus comprising in combination an evaporator, and means for withdrawing gaseous refrigerant from the evaporator, liquefying the refrigerant withdrawn and returning the liquid to. the evaporator, said means belng adapted to evaporate a portion of the liquid to cool the remaining liquid before returning it to the evaporator.

7. Refrigerating apparatus comprising in combination an; evaporator, means for withdrawing gaseous refrigerant from the evaporator and liquefying the refrigerant, and returning the liquid to the evaporator, and an insulated receiver for collecting the liquefied refrigerant before it is returned to the evaporator, said first mentioned means being adapted to evaporate a portion of the liquid in the receiver to cool the remainin liquid.

8. A. refrigerant control device or an absorption system comprising in combination a casing having a chamber therein, said chamber having a passage for the admission ofliquid and gaseous refrigerant, and a second passage (A) for admitting gaseous refrigerant, a second chamber having a passage (B), communicatin with the first chamber, and a passage (C) or conducting liquid refrigerant from the second chamber, valves for controlling passages A, B and C, and means responsive to pressure within the firstmentioned chamber for operating said valves either to open A and C and close B or to close A and C and open B.

9. A refrigerant control device for an absorption system comprising in combination a casing having a, chamber therein, said chamber having a passage for the admission of liquid and gaseous refrigerant, and a second passage (A) for admitting gaseous-re-' frigerant, a second chamber having a passage (B) communicating with the first chamber, and a passage (C) for conducting liquid refrigerant from the second chamber, aligned valves for controlling passages A, B and C, a biased valve stem for operating said valvessimultaneously, and means responsive to the pressure within the first-mentioned chamber for actuating the valve stem contrary to the bias.-

10. An absorption refrigerating apparatus comprising in' combination a generator-absorber, condensing means including a reservoir, and an evaporator, a connection between said reservoir and said evaporator, a connection between said evaporator and said generator-absorber, a valve in each of said connections, operative connections between said valves, and a device for actuating said valves simultaneously whereby the connection from the evaporator to the generator-absorber is signature.

HARRY B. HULL. 

